Roller drafting system for spinning machinery



y 1969 TAKUZO TOOKA ET AL 3,457,597

ROLLER DRAFTING SYSTEM FOR SPINNING MACHINERY Filed Sept. 15, 1967 2Sheets-Sheet 1 cuwuewwoum. 4901452 Deon/Iva; SYSTEM INVENT0R5 Tnzuzoroom A, HIDEd/QQ Ae4z4 MA Nd/ 1v? GA CHO u u N 20 H465 GA u/n, SUSUMUK/Iwnsn TA,

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July 29, 1969 TAKUZO TQOKA ET AL 3,457,597

ROLLER DRAFTING SYSTEM FOR SPINNING MACHINERY Filed Sept. 15, 1967 2Sheets-Sheet Z United States Patent U.S. Cl. 19-258 3 Claims ABSTRACT OFTHE DISCLOSURE A high-speed roller drafting system for a draw framecomprising a main drafting zone including five rollers, a front toproller in contact with and driven through a front bottom drive roller, asecond and third top roller, respectively, in contact with and driventhrough a second bottom drive roller, the front top roller being smallerin diameter than the front bottom roller and the second top roller beingsmaller in diameter than each of the front top roller and the secondbottom roller, said rollers of the main zone being so arranged that theextension of a straight line drawn from the center of the third toproller to the center of the second bottom roller intersects theextension of a straight line drawn from the center of the front toproller to the center of the front bottom roller, the nip between thesecond bottom roller and the second top roller being below the tangentdrawn from the nip between the front top roller and the front bottomroller to the upper side of the second bottom roller, and a tangentdrawn from the nip between the front top roller and the front bottomroller to the lower side of the second top roller being substantiallyperpendicular to the straight line connecting the centers of the fronttop roller and the front bottom roller.

This invention relates to an improved roller drafting system especiallyapplicable to the main drafting zone for a drawframe, in the spinning ofcotton, or staple fiber yarn.

The primary object of the invention is to provide a roller draftingsystem for spinning machinery capable of operating at very high speedwithout detriment to the quality of the sliver and so arranged as toavoid bearing and other drive problems.

Another object of the invention is to provide a roller drafting systemin which a second top roller of smaller diameter than conventional isdriven from a bottom drive roller rather than from a top drive roller asin conventional apparatus.

A further object of the invention is to provide a roller drafting systemin which the curvilinear arc of fiber touch at the input side of thefront draft zone is lengthened while the curvilinear arc of fiber touchat the output side of said zone is reduced for better drafting action.

Yet another object of the invention is to provide a roller draftingsystem in which the rollers are so positioned as to yield capability ofadjustment of the free length of fiber in the front drafting zone.

The invention provides a roller drafting system having the followingadvantages:

(a) The system forms only a small drafting-wave in the drafted materialand the sliver does not deteriorate even if the material is drafted at avery high speed;

(b) the system facilitates the adjustment of the roller 'ice setting orthe distance between the roller nips in the front drafting zone, whenchanging the drafted material;

(c) the system can be operated in a stable state because the forwarddirection of the delivery is inclined downwardly and because theadhesion, or the winding,

of fibers on the rollers, is reduced;

((1) the system lends itself to easy initiation of operation;

(e) the system can be easily equipped with a sliver thickness regulator;and

(f) the system is of sturdy construction and durable under very highspeed operation.

The novel features that are considered characteristic of the inventionare set forth with particularity in the appended claims. The invention,itself, however, both as to its organization and its method ofoperation, together with additional objects and advantages thereof, willbest be understood from the following description of specificembodiments when read in connection with the accompanying drawings,wherein like reference characters indicate like parts throughout theseveral figures and in which:

FIG. 1 is a diagram illustrating a preferred embodiment of theinvention,

FIGS. 2 and 3 are fragmentary diagrams illustrating technical principlesused or applied to the invention,

FIG. 4 is a diagram showing a conventional r-oller drafting system forcomparison with the invention, and

FIGS. 5 and 6 are diagrams similar to FIG. 1, but illustrating otherpreferred embodiments according to the invention.

Referring more particularly to the drawings, a preferred embodiment ofthe invention is diagrammed in FIG. 1 as comprising a roller draftingsystem for a drawframe with a five over four roller arrangement, theconstruction, elements, drives, etc., being conventional except for thedifferences mentioned hereinafter. The four bottom rollers 1, 3, 6 and 8are driven in a conventional manner from a driving shaft (not shown).The five top rollers 2, 4, 5, 7 and 9 are driven by friction from thebottom rollers. The main drafting zone M is composed of five rollers 2,1, 4, 3 and 5 so arranged and proportioned that the front top roller 2has a smaller diameter than the front bottom roller 1 and is in contactwith and driven by friction through said front bottom roller; the secondtop roller 4 has a smaller diameter than each of the front top roller 2and the second bottom roller 3 and is in contact with and driven byfriction through said second bottom roller; the extension of a straightline PQ drawn from the center of rotation P of the third top roller 5 inthe direction of and through the center of rotation Q of the secondbottom roller 3 intersects the extension of the straight line element RSdrawn from the center of rotation R of the front top roller 2 in thedirection of and through the center of rotation S of the front bottomroller 1; the point of contact a between the second bottom roller 3 andthe second top roller 4' is positioned below the tangent bf drawn fromthe point of contact b to the upper side. of the second bottom roller 3;and the tangent be drawn from the point of contact b to the lower sideof the second top roller 4 is substantially perpendicular to thestraight line RS which connects the center of rotation R of the fronttop roller 2 with the center of rotation S of the front bottom roller 1.

As shown in FIG. 1, the third and fourth top rollers 5 and 7 are incontact respectively with the second and third bottom rollers 3 and 6and are driven by fraction through said bottom rollers. The back toproller 9 is in contact with the back bottom roller 8 and is driven byfriction through said back bottom roller. The arrow indicates thedirection of flow of the sliver B.

In general, in order to raise the delivery speed of a drawframe, it isnecessary to increase the surface speed of each roller. Especially, thesurface speeds of the front rollers must be the highest of the drawframerollers. To increase the delivery speed of a high speed drawframe fromthe normal speed 150 m./ rnin. up to 500 m./min. with the same diameter(28 mm.), of the front bottom roller, it is necessary to increase therevolutions per minute of the front bottom roller, or driving roller,from 1,710 to 5,700 rpm. However, increase of the speed of drivingrollers up to a very high rate causes various troubles in bearings andother driving parts.

In order to overcome this trouble, the diameter of the front bottomroller 1 is increased according to the invention, so that the deliveryspeed may be increased while the revolutions per minute are kept below acertain value. For example, when the diameter of the front bottom roller1 is increased to 60 mm., and for a delivery speed of 500 M./min. it isonly necessary to raise the speed of the front roller 1 to 2,660 rpm.

In a conventional roller drafting system, increasing the diameter of thefront bottom roller necessitates wider roller setting, with theaccompanying problem of formation of a larger drafting wave. In theinvention, however, the proportioning and arrangement of the rollers, asdescribed above, prevents formation of a larger drafting wave. The fronttop driven roller 2, being smaller, can rotate faster and withstand thehigher revolutions per minute than the front bottom driving roller 1.Making the front top roller 2 smaller than the front bottom rollerprovides ample space for placement of the second top roller 4. Since thesecond top roller 4 is made smaller in diameter than the front toproller 2, said second top roller 4 can be installed in the space betweenthe front bottom roller 1, the front top roller 2, and the second bottomroller 3, and the setting ab of the front drafting zone, namely, thefiber pass from the point of contact a between the rollers 4 and 3 onthe input side to the point of contact 1; between the rollers 2 and 1 onthe output side, can be considerably shortened, so that the formation ofthe drafting wave is not increased even though the diameter of the frontbottom roller 1 has been increased.

In general, it is possible to improve the drafting action by placing thecurvilinear fiber touch region on a roller up to the same order as inthe case of employing aprons over drafting rollers. According to theinvention, as indicated previously in the arrangement of rollerscomposing the main drafting region, the extension of the straight linePQ drawn from the center of the third top roller 5 in the direction ofthe center of the second bottom roller 3 intersects the extension of thestraight line RS drawn from the center R of the front top roller 2 inthe direction of the center of the front bottom roller 1, the point ofcontact a "between the rollers 4 and 3 is placed below the tangent bfdrawn from the point of contact b between the rollers 2 and 1 to theupper side of the second bottom roller 3, and the tangent be drawn fromthe point of contact b between the rollers 2 and 1 to the lower side ofthe second top roller 4 is substantially perpendicular to the straightline RS. Therefore, the sliver B is in curvilinear contact with thesurface of the second top roller 4 in the are ac at the input side ofthe front drafting zone, while the sliver B has no curvilinear contactat the output side of the front drafting zone, or has only a smallcurvilinear contact in the arc bd on the front bottom roller 1 or on thefront top roller 2. In the front drafting zone having this inventivearrangement, better drafting action is attained with a smaller formationof drafting wave so that high quality sliver is produced even when thedrawframe is operated at high speed. The second top roller 4 may bevaried somewhat in position, as for example to occupy the broken lineposition of FIG. 1 without departing materially from the inventiveconcept and improved results.

For a better understanding of the theory of composing the curvilinearcontact region of sliver in drafting zone, the following detailedexplanation is given.

FIG. 2 and FIG. 3 indicate theoretic roller systems drafting sliver B inthe direction of the arrow. While the bottom rollers 1 and 3' are drivenby a driving shaft, each of the top rollers 2 and 4' is in contact witheither the bottom roller 1' or 3' and driven by friction through theroller 1 or 3' respectively.

In general, there are two modes of placing curvilinear arc of fibercontact on a roller. One is the mode in which the arc is placed at theinput side of the drafting zone, namely, the zone of fiber passage fromthe point of contact a between the rollers 4' and 3' at the input backside to the point of contact b between the rollers 2' and 1 at theoutput front side as shown in FIG. 2, and the other is the mode in whichthe arc is placed at the output side as shown in FIG. 3. The presentinventors have confirmed through tests that the curvilinear are ofcontact a'c at the input side as in FIG. 2 is considerably preferableover placing the curvilinear arc of contact d'b at the output side as inFIG. 3.

When the curvilinear region of fiber touch along arc a'c is in the inputside, as shown in FIG. 2, the speed of a fiber, whose trailing end hasleft the nip point a between the back rollers 4' and 3', and which isnipped by neither of two pairs of rollers, back rollers nor frontrollers, is maintained at the surface speed of the back rollers 3 and 4'or so-called low-speed, owing to a large interfiber friction at do,until the leading end of the fiber reaches the nip point b between thefront rollers 2' and 1'. Therefore, the speed change, at which such afiber is abruptly accelerated from the low-speed to the surface speed ofthe front rollers 1' and 2', or so-called high-speed, concentratessharply around a point near the nip point b, resulting in draftingaction and very little irregularity due to the drafting wave.

On the contrary, when the curvilinear region of fiber touch is placed atd'b in the output side as shown in FIG. 3, a floating fiber, which isnipped by neither of the nip points 12 nor a, tends to be accelerated assoon as the leading end of the fiber reaches the curvilinear are d'b'.In this case, the number of fibers touching the arc db' at a given timeis smaller than the number of fibers touching the arc a'c', so that itis indefinite at what point the fibers are accelerated; in other words,the high-speed fibers on the curvilinear arc db' are increased in numberas well as speed, but most of the above-mentioned floating fibers tendto accelerate and run at high-speed when more fibers are nipped by thefront nip point b, while most of the floating fibers do not accelerate,but tend to run at low-speed when less fibers are nipped by the frontnip point b'. Therefore, the FIG. 3 construction has the disadvantagethat, the speed change points are distributed over a wider range, andthe irregularity of the sliver is increased by the additional formationof the drafting wave.

Hence, the present invention contemplates that a curvilinear arc offiber touch ac is placed at the input side of the front draft zone andthe curvilinear arc of fiber touch db at the output side is diminishedor kept very short so that better drafting action may be accomplishedwith less formation of drafting wave.

Other functions and advantages of the system arrangement according tothe invention are described hereinafter. For example, tests have shownthat the optimum roller setting is obtained by the adjustment of thefree length ed, the most favorable free length being determined by UQL,the upper quartile length of the fibers in the drafted material.Therefore, when changing a drafted material to one of different staplelength, the inventive system provides for adjustment of free length cdto maintain the above-mentioned conditions of fiber touch on thecurvilinear arcs at both the input side and the output side of the frontdrafting zone, without any adjustment of the second bottom roller 3.This is done by making the second top roller 4 adjustably movable fromthe solid line position of FIG. 1 to the broken line position in FIG. 1,for instance, while still maintaining its surface contact with thesecond bottom roller 3, and out of contact with any other rollers.

In the conventional system of FIG. 4 1", 11, 6' and 8' are bottomrollers driven directly by a driving shaft; 2", 12, 7 and 9 are toprollers which are driven by friction through the bottom rollersrespectively. The arrow indicates the direction of flow of sliver B. isalso a bottom roller. It may be either driven directly by a drivingshaft or driven by friction through the top roller 12. The free lengthin FIG. 4 corresponding to cd in FIG. 1 can be adjusted by shifting thesecond bottom roller 10 backward or forward. This has the disadvantagethat the adjusting range of the shift is small and the adjustingoperation and machine maintenance are complicated and diflicult becausesaid roller 10 is a bottom roller placed between the bearing brackets ofadjacent bottom rollers which are rigid and rather bulky.

By contrast in the inventive system of FIG. 1, the roller to be shiftedfor obtaining the optimum free length is the second top roller 4 in thedriven roller side. Thus, the setting ab in the front drafting zone canbe adjusted according to the staple length of the fiber material withoutshifting either bottom roller 1 or 3 in the driving roller side.Therefore, this arrangement provides a simple yet sturdy draftingsystem, is very easy to handle, and yields the advantage of rapidadjustability of settings for free length of fiber according to the meanstaple length of the material being processed.

Tests have verified that the curvilinear fiber touch are ac in the inputside of a front drafting zone must be 6 mm. or more for the arc acto-function effectively, as ex plained above, while the curvilinearfiber touch arc db in the output side must be 4 mm. or less to avoid theexplained disadvantage of said are db. To obtain an arc ac of 6 mm. ormore, it is preferable to increase the diameter of the second top roller4 provided this is allowed by the spacing of the front bottom roller 1,the front top roller 2, the second bottom roller 3, and the third toproller 5 as well as the required free length adjustable range cd. It hasalso been found preferable by tests that the diameter of the second toproller 4 be more than mm.

It is preferable to employ grooved metallic rollers as each the thirdbottom roller 6, the fourth top roller 7, the back bottom roller 8, andthe back top roller 9 for the five over four roller drafting system on asuper high speed and high draft drawframe according to the inventionshown in FIG. 1. This is especially so as to the back bottom roller 8and the back top roller 9 and to mesh one of them with the other so asto grip the sliver more firmly, and for better control of the sliverdrafted.

In the embodiment shown in FIG. 1, the second bottom roller 3, the thirdbottom roller 6, and the back bottom roller 8 have equal diameters tomake possible the convenience of their mutual exchange. This alsoapplies to the third top roller 5, the fourth top roller 7 and the backtop roller 9.

The direction of the tangent of the front bottom roller 1 and of thefront top roller 2 at the point of contact b can be changed through awide range to suit process demands, by swinging the assembly of thefront bottom roller 1, the front top roller 2, and the second top roller4 around the axis Q of the second bottom roller 3. The sliver from theroller drafting system is delivered through a coiler (not shown, butplaced forwardly and downwardly) and then stored in a can. The sliver inthe form of web as delivered between the front bottom roller 1 and thefront top roller 2 runs in the direction of the tangent at the point ofcontact b. On a super high speed drawframe, the momentum of the runningsliver is so large that it is not desirable, from the viewpoint ofstability, to guide the sliver through the coiler which is offset fromsaid tangent. The roller drafting system according to the invention,therefore, improves the stability of the operation, because thedirection of said tangent can be changed through a wide range withoutaffecting the composition of the front drafting rollers.

Considering the initiation of the drafting of silver on a conventionalfour over five roller drafting system as in FIG. 4, when the silver isfed between the back bottom roller 8 and the back top roller 9, thefibers tend to flow forward and downward at an angle with the tangentdrawn at the point of contact between the rollers 12 and 11 owing to theweight of the fibers. So that the fibers may be deposited between thesecond bottom roller 10 and the third bottom roller 11, it becomesnecessary to remove the second top roller 12, to guide the depositedfibers to the nip between the front bottom roller 1" and the front toproller 2", and then to re-start the machine. Thus, the initiation, orstarting operation, involves two steps, with resulting delay andunsmoothness of a sliver when new slivers are lapped in.

On the contrary, on the roller drafing system according to the inventionas shown in FIG. 1, the locus of the fibers ejected from the third toproller 5 deviates downward from the tangent of the third top roller 5and the second bottom roller 3 at the point of contact e due to thegravitational force and reaches the surface of the second top roller 4along the surface of the second bottom roller 3. Although the fibersejected from the second top roller 4 also tend to flow downward, thefibers are carried on the surface of the front bottom roller 1 whoseupper surface is running forward and then nipped by the front top roller2. Thus, in the initiation of the drafting operation, the fibersautomatically reach the nip between the front bottom roller 1 and thefront top roller 2, simply by supplying the fibers B to the nip betweenthe back bottom roller 8 and the back top roller 9. It is anadvantageous feature of this invention that the initiation is performedvery smoothly in such a way, and with only one step.

The tendency toward fiber adhesive, or winding, on the front bottomroller is a big problem particularly in high speed operations. The useof the front bottom roller 1 with a larger than conventional diameter inthe invention is very elfective for preventing such trouble.

Most drafting systems utilize a sliver thickness regulator, thethickness being controlled by varying the revolutions per minute of thefront bottom roller according to the thickness detected. In a super highspeed drawframe,

the revolutions per minute of the front bottom roller must be higherthan conventional. Therefore, to increase the speed of conventionalmachines the regulating systems of the front rollers should be reformedfor higher revolutions per minute, but this is rather difficult. In thepresent invention, it is not necessary to increase the revolutions perminute of the front bottom roller 1 up to as high a level, even for asuper high speed operation of the drawframe, because of the largerdiameter of said roller. Thus, the regulating system may be attached tothe drawframe without major reconstruction. This is also an advantage ofthe invention.

In the second embodiment illustrated in FIG. 5, the fourth top roller 7is reduced in diameter and the center of said roller 7" is placed moreforward, while the center of the third bottom roller 6 is placed back ofthe center of the fourth top roller 7". The back bottom roller 8 isplaced higher than the same roller 8 shown in FIG. 1, and the center ofthe back top roller 9 is placed in front of the center of the backbottom roller 8. With this arrangement a curvilinear fiber touch arc isobtained in the input side with no or very little curvilinear fibertouch arc in the output side of both the intermediate drafting zone andthe back drafting zone, or, if desired, either in the former or in thelatter. The intermediate drafting zone is composed of the rollers 5 and3 and the rollers 7" and 6. The back drafting zone is composed of therollers 7" and 6 and the back rollers 9 and 8. With the de- 7 scribedarrangement it is possible to reduce the free length of each draftingzone according to the UQL of the fiber material without reducing thediameter of each bottom roller to attain the draft control with littleformation of drafting wave. Therefore, it is possible to increase thetotal draft of the roller drafting system by increasing the draft ineach drafting zone and to obtain a product having less irregularity dueto the drafting wave. It is further preferable to make the back toproller 9 larger than the fourth top roller 7" to nip the sliver morefirmly at the inlet of the system. It will be noted that the describedarrangement is such that an extension of the straight line drawn fromthe center of the third bottom roller 6 to the center of the fourth toproller 7" intersects the extension of the straight line drawn from thecenter of the back bottom roller 8 to the center of the back top roller9" and the tangent from the nip of rollers 7" and 6 to the underside ofroller 9 is substantially perpendicular V p to said first line as in themain drafting zone described for FIG. 1.

In the third embodiment illustrated in FIG. 6, the system is so arrangedthat the intermediate and back drafting zones are inclined upwardlytoward the rear, the back bottom roller 8 being placed slightly abovethe third bottom roller. This arrangement is used when required by spaceand other factors, and there is no difference in result or principlefrom the FIG. 1 embodiment. Thus, the drafting zone back of the thirdbottom roller 6 and the drafting zone in front of the second bottomroller 3 can be relatively inclined through an arbitrary angle withconsiderable freedom, without changing the composition of the draftingzone between rollers 6 and 3. It is thus a feature of the invention thateach drafting zone can be fore, is not to be restricted except insofaras is necessitated by the prior art and by the spirit of the appendedclaims.

What is claimed is:

1. A roller drafting system for spinning machinery comprising a maindrafting zone including a front top roller in contact with and driventhrough a front bottom drive roller, and second and third top rollersrespectively in contact with and driven through a second bottom driveroller, and an intermediate drafting zone including said second bottomand third top rollers, and a fourth top roller in contact with anddriven by a third bottom drive roller, the front top roller beingsmaller in diameter than the front bottom roller and the second toproller being smaller in diameter than each of the front top roller andthe second bottom roller, the second top roller being adjustably movablealong the surface of the second bottom roller, said rollers of the mainzone being so arranged that the extension of a straight line drawn fromthe center of the third top roller to the center of the second bottomroller intersects the extension of a straight line drawn from the centerof the front top roller to the center of the front bottom roller, thepoint of contact between the second bottom roller and the second toproller being below the tangent drawn from the point of contact betweenthe front top roller and the front bottom roller to the upper side ofthe second bottom roller so that the length of the are on the second toproller from the point of its contact with the second bottom roller tothe point of its contact with the common tangent of the lower surface ofthe second top roller and the upper surface of the front bottom rolleris at least 6 mm., a tangent drawn from the point of contact between thefront top roller and the front bottom roller to the lower side of thesecond top roller being substantially perpendicular to the straight lineconnecting the centers of the front top roller and the front bottomroller so that the length of the are on the front bottom roller from thepoint of contact between the from bottom roller and the said commontangent to the point of contact between the front bottom roller and thefront top roller is no greater than 4 mm., and a tangent drawn from thepoint of contact between the third top roller and the second bottomroller to the lower side of the fourth top roller is substantiallyperpendicular to the straight line connecting the centers of the thirdtop roller and the second bottom roller so that the length ofcurvilinear arc of fiber touch on each of the second bottom roller andthird top roller on the output side of said intermediate draft zone isno greater than 4 mm.

2. A roller drafting system as claimed in claim 1, wherein said fourthtop roller has a smaller diameter than the third bottom roller and isplaced forward thereof.

3. A roller drafting system as claimed in claim 1, wherein the diameterof said second top roller is greater than 15 mm.

References Cited UNITED STATES PATENTS 1,579,414 4/1926 Thoma 19281 XR1,583,893 5/1926 Meier 19283 2,076,609 4/1937 Adams 19283 XR 2,624,9191/ 1953 Spencer 1926O XR FOREIGN PATENTS 127,702 6/ 1919 Great Britain.642,419 9/ 1950 Great Britain. 79,594 V 12/ 1918 Switzerland.

DORSEY NEWTON, Primary Examiner US. Cl. X.R.

